Slewing access ramp for vehicles

ABSTRACT

A slewing access ramp for providing a passageway between a ship and a quay and pivotally connected to the ship so that it may be swung either upwards into an inoperative upstanding stowed position on board ship or downwards into an operative working position to bear onto the quay with its outboard end and comprising means for variable connection with said ship so that the ramp may swivel in parallel relation to a relatively horizontal plane about at least one substantially vertical geometrical axis of rotation so that in its lowered working condition the relative angular position of its longitudinal direction with respect to the ship be selectively adjustable.

ited States Patent [1 1 Kummerman 1 Apr. 29, 1975 SLEWING ACCESS RAMP FOR VEHICLES [75] lnventor: Henri Kummerman, Geneva,

Switzerland 221 Filed: July 18,1973

21 Appl. No.: 380,469

2,641,785 6/1953 Pitts 14/71 2,688,761 9/1954 Good 14/71 3,110.048 ll/l963 Bolton l 14/71 3,468,280 9/1969 Williams 14/71 X Primary Examiner-Nile C. Byers, Jr. Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin [57] ABSTRACT A slewing access ramp for providing a passageway between a ship and a quay and pivotally connected to the ship so that it may be swung either upwards into an inoperative upstanding stowed position on board ship or downwards into an operative working position to bear onto the quay with its outboard end and comprising means for variable connection with said ship so that the ramp may swivel in parallel relation to a relatively horizontal plane about at least one substantially vertical geometrical axis of rotation so that in its lowered working condition the relative angular position of its longitudinal direction with respect to the ship be selectively adjustable.

39 Claims, 26 Drawing Figures SLEWING ACCESS RAMP FOR VEHICLES The present invention relates generally and is essentially directed to a movable device forming an access ramp or like gangway, horse or bridge means adapted to provide a communication passage, conveyance, transhipment or like means between on the one hand any vehicle in particular of land or marine character such as for instance a ship, boat or like floating vessel and on the other hand an outside loading or unloading area or platform such as a quay, pier, wharf, bank, shore or beach or even another vehicle as well as the various applications and uses resulting from implementing same and the systems, arrangements, assemblies, appliances, equipments, plants and installations provided with such devices or apparatus.

There are already known in particular in naval or marine applications, transport or cargo ships of the roll on-roll off kind for conveying for instance wheeled vehicles and in particular automotive or motor vehicles or various goods and products. In the case of automotive vehicles, the shipping and unshipping thereof are effected by their own self-contained or independent propulsion or drive means by rolling individually or separately and directly on a movable access ramp interconnecting the ship (and more specifically the loading deck or flooring thereof) and the quay or the like. In the case of general cargo, such a ramp is also used directly by automotive handling carriages, trucks or like carts or wheeled cargo-handling gears running on said ramp in a shuttle-like manner enabling them to have direct access to the ship and to come back to the quay for loading or shipping and unloading or unshipping goods and like cargoes. For this purpose the ship is provided at least at one end thereof, i.e. generally aft or astern or possibly also afore at the bow with at least one large-sized ramp of the kind pivotally connected with its inboard end (or forward end when located aft) to the ship for swinging motion in parallel relation to a relatively vertical plane so that it may be swung upwards, i.e. lifted or raised to a substantially inoperative upstanding position in a stowed or lashed condition on board ship during the sea trip of the latter and downwards i.e. lowered into an operative working position to bear onto the quay with its opposite, i.e. outboard (or outside or rear) end. As the ship is generally moored or secured along the quay berth in parallel relation thereto, said ramp, when it is located astern, i.e. at the rear end of the ship, is generally positioned slantwise in its lowered working condition with respect to the longitudinal central vertical plane of the ship so that the longitudinal direction of the ramp is at an angle of about 45 with respect to the longitudinal direction of the ship. Such a ramp thus enables various kinds of wheeled vehicles to be taken aboard the ship for instance from quays which are not fitted up or suited for such a use.

This ramp known from the prior art exhibits the serious disadvantage of being placed in dissymetrical relation to the longitudinal vertical central plane of the ship or vehicle of any kind served by the ramp, so that the ship or vehicle of any kind is required to come alongside always with the same ship side in view of the stationary attitude or orientation of the ramp in its working position or operative state.

One main object of the invention is therefore to remove the aforementioned drawback inherent with the prior known state of the art by providing a selectively orientable, for instance swivelling or slewing ramp enabling the access of the vehicle (for example of a vessel) or quay whatever the relative angular position of the vehicle with respect to the quay, i.e. irrespective of the attitude of the vehicle. For the purpose of solving this technical problem the invention proposes a ramp which is characterized in that it comprises means for variable connection with said vehicle so that it may be angularly positioned or oriented in parallel relation to a horizontal plane, for instance swivelled or slewed about at least one relatively vertical axis of rotation, so that in the lowered state or downward swung condition, the relative angular position of its longitudinal direction be selectively adjustable with respect to said vehicle.

According to a further characterizing feature of the invention said ramp is pivotally connected with its inboard or innermost end to at least Onecarriage, trolley or like slide-rest movable along a forced guiding track or runway provided on the vehicle along a substantially planar curved path of travel, preferably at least partially and approximatively in the shape of an arc of circumference.

Such an arrangement according to the invention exhibits the significant advantage of enabling an arbitrary orientation of the ramp into at least three different relative angular positions in particular in the case of a ramp mounted on a ship at the rearward end or astern thereof with said forced guiding track or runway located symmetrically with respect to the longitudinal vertical central plane of the vessel. In such a case the ramp may thus be arranged either to extend substantially along the longitudinal axis of the ship in outwards aligned extended registering relationship therewith or in a slant position to starboard or in a slant position to port, the ramp making in each slant position for example an angle of about 40 with the longitudinal direction of the vessel. This multiple-orientation capability of the ramp dispenses with the aforesaid requirement of coming alongside of the prior known state of the art by making the use of the ramp substantially independent practically or to a large extent of the effective angular mooring position of the ship or more generally of the attitude of the vehicle to be served in relation to the quay.

According to the invention, the variable orientation of the ramp is carried out by a rotary displacement of its pivot axis along a substantially horizontal curved path of travel, i.e. about a stationary vertical axis of rotation located outside of the ramp. The same effect or result could obviously be achieved by a true pivotal motion of the ramp about a stationary vertical axis of rotation meeting or intersecting the ramp or at least the horizontal axis of rotation thereof (said curved path of travel of its pivot axis being then reduced to a point or centre of rotation of said axis) but such an approach would be disadvantageous in requiring a longer effective total useful length of the ramp.

In the aforesaid embodiment the ramp is pivotally connected with its inboard or innermost end for swinging motion about a substantially horizontal geometrical axis of rotation to a carriage, truck or like trolley which is forced guided on both sides thereof and movable on and in a substantially horizontal runway or like trackway in the shape of an arc of circumference concentric with the theoretical vertical geometrical axis of swivelling or slewing motion of the ramp and recessed, sunk or embedded into the ships deck astern thereof. Such an arrangement may sometimes be somewhat inconvenient in view of the presence of a surface feature, discontinuity, irregularity or unevenness owing to the trenching or stepped character, hollow or like recess due to the provision of the runway for the carriage in the ships deck. Another embodiment of the invention enables removal of such a drawback by providing a system for relative angular orientation of the longitudinal vertical central plane of the ramp thereby allowing retention of the advantage of a substantially flat and even top surface of the deck without any surface irregularity, discontinuity or unevenness. For this purpose and according to a further characterizing feature of the invention, said ramp comprises means enabling it to swivel or slew alternately and separately about at least one relative vertical axis and preferably two relative vertical axes of rotation each one having a stationary position, respectively, through at least two transversely spaced points of its inboard end which are for instance adjacent to the extreme opposite corners of said inboard end, said points forming points of pivotal connection of said ramp with the ship and each one of said points may be releasably locked or held against motion at the location of one associated vertical axis or rotation whereas the other point of pivotal connection is freely displaceable about the former in concentric relation thereto, the relative horizontal geometrical axis of rotation of said ramp extending through said points of pivotal connection.

According to still a further characterizing feature of the invention, said ramp is connected removably, i.e. in a disconnectable manner with at least both of said two points of pivotal connection, which are provided with two pivotal connecting members having a common horizontal geometrical axis of pivotal connection, respectively, to two rotary pivots forming corresponding hinge supports or holders having their own vertical axes of rotation which are rotatably fitted at a stationary location on said vehicle or ship, each one of the two points of pivotal connection being alternately displaceable separately, when disconnected from its corresponding pivot, in the stationary relative horizontal plane of said common axis of pivotal connection along a substantially circular arcuate path of travel about the other point of pivotal connection kept in stationary position wherein it is coupled to its associated pivot, so as to selectively enable the slewing of said ramp on the one hand with said other point of pivotal connection thereof about the vertical axis of rotation of the corresponding pivot and on the other hand about said common horizontal geometrical axis of pivotal connection of the two pivotal connecting members.

As known per se, the ramp may consist of three successive ramp sections pivotally interconnected in the longitudinal direction so as to make the ramp foldable or collapsible in view of the intermediate ramp section being foldable back or swingable downwards against and along the innermost or inboard end ramp section which is secured and suspended on both sides towards or adjacent to its outer or outboard end from a pair of handling wire rpopes, respectively, reeved over loose guide pulleys or like idle sheaves pivotally connected to the tops of a pair of king posts or like masts'of the ship, these wire ropes being taken up or wound up on a pair of winches, respectively. The outermost or outboard end ramp section serves as a supporting pad for bearing engagement with or resting on the quay. A ramp of such a kind is disclosed in the French patent application No. 72,23,373 filed on June 28, 1972 and its first certificate of addition No. 73,19,51 1 filed on May 29, 1973 and comprises at least one operating wire rope for controlling the relative upward swinging motion of the intermediate ramp section into an extended position at least approximatively in aligned registering relation to the innermost end ramp section in the lowered working position thereof. This operating wire rope for relative extension of said intermediate ramp section is connected through at least one guide pulley or sheave to the top of each aforesaid king post or mast so as to provide a stationary fastening point for said wire rope with a view to produce a tractive reaction force effective to achieve said relative extension of said intermediate ramp section during the gravity-operated downward swinging motion of the innermost end ramp section under the action of its own weight, which innermost ramp section is constantly suspended from its aforesaid handling wire rope. This device, as proposed in the aforesaid French patent application No. 72,23,373 filed on June 28, 1972 and its first certificate of addition No. 73,19,511 filed on May 29, 1973 exhibits the inconvenience that the longitudinal central relative vertical plane of the ramp has a stationary angular position with respect to the longitudinal vertical central plane of the vehicle or vessel, so that it is not orientable at will in parallel relation to a horizontal plane. Another main object of the present invention is to adapt in combined relationship the ramp of the kind defined by said French patent application No. 72,23,373 filed on June 28, 1972 and its first certificate of addition No. 73,19,511 filed on May 29, 1973 to the principle of the slewing or swivelling ramp arrangement which is orientable about a vertical pivot axis in accordance with the present invention.

Instead of being mounted aft or at the rear of any vessel or vehicle, the ramp according to the invention could as well be provided in any side opening of the vehicle, for example in a cargo port provided in the side of the ship.

The invention will be better understood and further objects, characterizing features, details and advantages thereof will appear more clearly as the following explanatory description proceeds with reference to the diagrammatic accompanying drawings given by way of non-limiting examples only illustrating variously presently preferred specific forms of embodiment of the invention and wherein:

FIG. 1 shows a fragmentary perspective view of the rearmost end portion of a ship moored slantwise near a quay and fitted with a ramp according to the invention placed in the lowered working condition in a central position in extension of the longitudinal axis of the ship and resting in bearing engagement on the quay;

FIG. 2 is a fragmentary view seen from the starboard side aft of the ship with the ramp in said working position;

FIG. 3 is a fragmentary top view of the rearmost end portion of the ship assumed to be moored alongside the quay in parallel relation thereto with the ramp arranged in slant working position to starboard, this Figure also showing the two other possible relative angular positions of the ramp;

FIG. 4 is an end view from astern as seen in the direction of the arrow IV of FIG. 3, of the ship with the ramp in a slant working position to starboard;

FIG. 5 is a fragmentary view, drawn at a larger scale and in cross-section taken along the broken line V-V of FIG. 6, showing the carriage or trolley for pivotal connection of the ramp to the ship, together with its guide rails mounted on the ship;

FIG. 6 is a fragmentary top view, drawn at a smaller scale and looking in the direction of the arrow VI of FIG. 5, showing the stern of the vessel with the ramp in the central lowered working position pivotally connected to its trolley movable on concentric curved guide rails;

FIG. 7 is a fragmentary view, drawn at a larger scale and similar to FIG. 5, showing an alternative embodiment with an automotive trolley or truck;

FIG. 8 is a perspective view similar to FIG. 1 and showing a modification of the arrangement comprising a turn-table or the like;

FIG. 9 is a partial top view, with parts broken away, of the circled detail IX of FIG. 8;

FIG. 10 shows a further embodiment according to a fragmentary top view of the innermost end portion of the ramp in the lowered working position thereof, mounted on the poop or stern of a vessel and provided with a system for varying the relative angular horizontal orientation by alternately slewing separately about either of a pair of separate vertical axes of rotation;

FIG. 11 shows, at an enlarged scale, an axial vertical section through a vertical pivot with combined hinged connection for swivelling in parallel relation to a horizontal plane, for each point of pivotal connection between the ramp and the ship;

FIG. 12 is a top view of an alternative embodiment of the system shown in FIG. 10, showing a modification of the operating means controlling the slewing motion;

FIG. 13 is a top view, drawn at a smaller scale, of a foldable and pivotally connected ramp consisting of three ramp sections, in the extended and lowered working position thereof, pivotally connected to the ship through a pair of trucks movable within a circular arcuate runway provided on the vessel forallowing to selectively vary the relative horizontal angular orientation of the ramp;

FIG. 14 is a side view of the ramp of the previous Figure in its inoperative, folded and upward swung stowed position in a lashed condition on the ship;

FIG. 15 is an enlarged front view from aft, i.e. as seen from the left-hand end of the vessel in the direction of the horizontal arrow XV in FIG. 14, the illustration of the ramp having been omitted to show the structure located behind, i.e. before the ramp;

FIG. 16 is a fragmentary side view, drawn at a larger scale with parts broken away, of the adjacent mutually pivotally interconnected ends of the innermost end and intermediate ramp sections, respectively, showing in particular the buttressing device for locking the pivotal connection in a selectively adjustable manner;

FIG. 17 shows, at a larger scale, a separate top view of a carriage or trolley forming a wheeled bogie or truck and hinge support for the ramp;

FIG. 18 is a cross-section taken upon the line XVIII- XVIII of FIG. 17, of a wheel-carrying axle of said truck;

FIG. 19 is a cross-section taken upon the line XIX- XIX of FIG. 17, along the vertical axis of a horizontal roller for lateral guiding of said truck;

FIG. 20 is a section taken upon the line XXXX of FIG. 17, showing a lug or leg portion of a clevis or yoke forming a bracket-like holder for the pivotal connection bearing of the ramp on the truck;

FIG. 21 is a fragmentary enlarged sectional view taken upon the line XXIXXI of FIG. 22 and showing the uppermost portion forming the top jib or like outrigger arm of the king post or like derrick mast from which the ramp is hanging and which is located to port side, said view showing a guide pulley for the operating wire rope controlling the relative extension of the intermediate ramp section and a swivelling stationary pulley block or tackle block for the ramp handling wire rope, the swivelling pulley associated with said stationary pulley block having been omitted;

FIG. 22 is a rear front or end view as seen from the left-hand side of said port side king post or derrick mast looking in the direction of the horizontal arrow XXII in FIG. 21, said stationary pulley block having been omitted;

FIG. 23 is a fragmentary top view of the king post or derrick mast shown in FIG. 22, illustrating the port side guide pulley for the operating cable controlling the relative extension of said intermediate ramp section;

FIG. 24 is a partial view in section taken upon the line XXIV-XXIV of FIG. 22 and showing a swivelling guide pulley for the handling wire rope;

FIG. 25 is a top view of the device of FIG. 24; and

FIG. 26 is a partial view in cross-section taken upon the line XXVI-XXVI of FIG. 22 and showing the feather or lug for pivotal connection of said stationary pulley block to its vertical pivot.

According to the examplary embodiment shown in FIGS. 1 to 4, a ship, denoted generally by the reference numeral 1 and of which the stem or poop only is shown is moored near or adjacent to a quay 2 for example according to a slant orientation, so that the longitudinal direction of the ship is at an angle with the direction of the edge of the quay. The rear portion or stem of the ship is fitted with a movable access ramp 3 consisting of three successive ramp sections, namely an inboard or foremost ramp section 3a, a central or intermediate ramp section 3b and a rearmost or outboard section 3c which are pivotally connected to each other in the longitudinal direction in substantially aligned or mutually registering extension of each other through pivot hinges or the like at 4, 4', respectively. The outermost or outboard ramp section 30 desirably exhibits the shape of a bearing pad or like ground-engaging plate serving to support the ramp onto the quay 2. The innermost end ramp section 3a is desirably made wider towards its innermost or inboard end with which it is pivotally connected at 5 to the vessel 1. This kind of construction exhibits the advantage of allowing a maximum compensation for the difference in level between the loading deck or flooring 6 of the ship and quays 2 of various heights or for a difference in level of the sea surface in view of the tides. The ramp sections 3a and 3b are desirably provided with guide railings or like protective devices 7 along their opposite longitudinal edges or sides.

With reference to FIGS. 5 and 6 which show the system for movably connecting the ramp section 3a to the ship, this connecting system comprises a wheeled truck or trolley 8 including a frame 9 with a horizontal apparent contour substantially in the shape of a segment of a circular annulus or like ring preferably substantially symmetrical with respect to the longitudinal centre line 10 of the ramp 3. This frame 9 carries for example at its upper portion at least one end and preferably two clevis or like yokes 11 to which the ramp section 30 is pivotally connected at by means of lugs or like feathers or tongs 12 respectively fast with corresponding side frame members or like girders or spars of the ramp section 3a about substantially horizontal coaxial pivot axes extending at right angles to the longitudinal centre line of the ramp. The frame 9 of the carriage 8 is mounted on carrying run wheels or like rollers 13 having substantially horizontal respective axles and located on either side of the frame for riding on or rolling in a curved guide track desirably consisting of a pair of guide rails in the shape of transversely or radially spaced concentric arcs of circumference 14 arranged astern of the ship 1 preferably in symmetrical relation to the longitudinal vertical centre plane 15 of the vessel while extending desirably over the major part of the 10- cally available width of the ship at the rear portion thereof. Each rail consists for example of a sectional structural beam or girder with an l-shaped crosssectional contour and the rollers 13 are adapted to run on the top surface of the inner bottom or lower flange of the associated sectional beam, the axle of each roller being directed in a radial direction, i.e. in a normal direction with respect to the track or runway. The frame of the carriage 9 is also provided on either side thereof with lateral guide rollers 16 having respective substantially vertical axes of rotation and engaging through rolling contact the inner vertical wall, respectively, of the web of each associated guide rail 14. The truck 8 and its guideway 14 are desirably located lower down than or below the level of the deck or flooring 6 of the vessel served by the ram 3 and for instance within a pit forming a throw, step or like lower landing 17 or within a like recess in the ships deck. The height of the carriage 8 is such that the top runway or carriage-way of the rame 3 or at least the inner adjacent end of said ramp is substantially at the same level as the deck 6 of the vessel or aligned therewith. For providing surface continuity between the ramp 3 and the deck 6, at least one and preferably a plurality of transversely juxtaposed flaps or like hinged leaves 18 are pivotally connected separately at 19 to the adjacent inner end of the ramp section 3a so that they may be folded back individually against said ramp or swung downwards onto the flooring or deck 6 of the vehicle thereby to cover and span the pit 17 containing the trolley 8 and its guide track 14 while allowing vehicles to cross same or pass thereover.

Owing to the aforesaid extension of the guide rails 14, the trolley 8 is thus displaceable substantially from one side of the ship to the other while being guided through engagement on either side keeping the rollers 13 retained or entrapped between the overlying flanges of the guide rails.

To allow the handling operation of the ramp, the latter is secured on both sides with at least two intermediate points 20 thereof, respectively, to at least two handling wire ropes or chains 21 taken or wound up on two winches or the like 22, respectively, mounted on the ship as known per se. Each wire rope 21 is thus desirably reeved over a guide pulley 23 pivotally connected to an overhead or elevated structure of the ship or vehicle, such as for instance a derrick mast, king post or like standard or upright 24 fast with the ship, so that each pulley 23 may swivel about a substantially vertical axis, both pulleys 23 and therefore both derrick masts or king posts 24 being preferably located symmetrically with respect to the vertical medial or centre plane of the guide track 14. In a manner known per se, the stationary fastening points 20 of the handling wire ropes 21 are desirably secured adjacent to the outer end of the innermost ramp section 3a. This innermost ramp section 3a thus remains constantly suspended from the handling wire ropes 21 at least in its lowered working position and possible also in most of its intermediate positions between its extreme lowered and raised positions, respectively. The swivelling pulleys 23 are desirably located towards the top of their respective supporting derrick masts or king posts 24 whereas the winches 22 are located at the bottoms or feet of these king posts.

Locking means are provided for holding the ramp 3 against motion in each or any relative angular position in the lowered and/or upwards lifted condition. For this purpose the truck 8 may be locked in any relative position on its guide rails 14 for instance through a locking arrangement with a stop bolt or like locking pin insertable through a corresponding hole 25 of the frame of the truck 9 into a stationary opening provided in a structure rigidly connected to the ship, such as for example the top or upper flange of a rail 14. To stop the ramp 3 in its vertically raised position 3A shown in dash-dotted lines on FIGS. 2 and 4, in which raised position the ramp 3 is in its relative central angular position, i.e. in registering relation to the longitudinal centre line of the ship 1, there is provided at least one and preferably two suitable stop, rest or abutment means 26 rigidly connected for example to the superstructures 27 of the vessel 1 as well as at least one and preferably two locking members 28 which are for example mechanically, hydraulically, pneumatically or electrically operated possibly in an automatic manner and adapted to retain the ramp in the upwards lifted position, said locking members being located on the ramp and in particular on the section 3a thereof or on the ship. Moreover there are provided at least one and preferably two servo-motors or like actuators 29 for instance of the linear displacement ram type mounted together for instance on either side on the innermost end and intermediate ramp sections 3a and 3b, respectively, at the pivotal connection 4 thereof and likely to be actuated synchronously and reversibly to cause a limited relative rotation of one or each one of the two adjacent ramp sections about their pivotal connection 4 in the direction of lifting said pivotal connection, i.e. in the direction of moving both ramp sections 3a, 3b towards each other with their bottom or external faces.

Finally the ramp 3 is fitted with self-acting control means for keeping the handling wire ropes 21 taut or stretched with a substantially constant tension in the lowered working position of the ramp, the poweroperated winches 22 being preferably phase-locked in follow-up relationship to said control means which consist for instance of at least one and preferably two sensor, detector, feeler or like pick-up members 30 (FIG. 2) secured to the intermediate ramp section 3b towards the outer end portion thereof, for instance on either side of and underneath same, so that they may bear 

1. A movable device forming an access ramp to interconnect a vehicle and aN outside platform, said ramp being pivotally connected to the vehicle so as to be swingable upwards into an inoperative substantially unstanding position stowed on said vehicle and downwards into an operative outward projecting working position, wherein the improvement consists in that said ramp comprises means for variable connection to said vehicle so that it may be slewed in parallel relation to a horizontal plane about at least one substantially vertical geometrical swivel axis whereby in its lowered configuration, the relative angular position of its longitudinal direction is selectively adjustable with respect to said vehicle, said last-named means comprising posts, at least two selectively operable winches associated with said posts and at least two handling ropes connected between respective of said winches and said ramp and selectively windable up on said winches.
 2. A device according to claim 1, including at least one truck and a forced guiding runway provided on said vehicle in which said truck is movable along a substantially flat curved path of travel having at least partially and approximately the shape of an arc of circumference, said ramp being pivotally connected with its innermost end to said truck.
 3. A device according to claim 2, wherein said truck to which said ramp is connected includes a frame of arcuate configuration in parallel relation to a horizontal plane and travelling carrying wheels and wheels, and a pair of concentric curved rails, respectively, forming said guiding runway in which said named wheels are bilaterally guided.
 4. A device according to claim 3 including a rack mounted on one of said rails, a motor on said truck and gear means driveable by said motor and meshing with said rack to effect slewing motion of said ramp.
 5. A device according to claim 3 including motor means mounted on said truck and means for driving at least some of said wheels by said motor means.
 6. A device according to claim 2, wherein said truck is of automotive character.
 7. A device according to claim 2 comprising swivel bearing means pivotally connected towards opposite transverse corners of the innermost end to said ramp at least a pair of travelling rucks connected to said swivel bearing means and each truck comprising a pair of axles supporting carrying travelling side wheels and a pair of horizontal wheels for lateral guiding, each one having a vertical axis of rotation, said horizontal wheels being mounted at the lengthwise opposite ends, respectively, of the truck frame.
 8. A device according to claim 1, wherein said ramp is attached on both sides of two intermediate points thereof to respective of said two handling wire ropes, respectively, winding up on said two winches, guide pulleys respectively pivotally connected to said post of said vehicle so that each may swivel about a substantially vertical axis, respective handling ropes passing around respective of said pulleys and both pulleys being located in symmetrical relation to the vertical plane bi-secting the angle representing the maximum amplitude of slewing motion of said ramp.
 9. A device according to claim 5, wherein said ramp comprises three successive ramp sections hingedly interconnected in the longitudinal direction, the outermost end section serving as a bearing pad resting on a platform in lowered working position of said ramp, whereas the innermost end section is secured to said handling wire ropes towards its outer end and wherein said winches act upon said handling ropes to raise and lower said ramp and in at least said lowered working position of said ramp, said innermost end ramp section remains always suspended from said handling ropes, and at least one ram-type actuator of the linear displacement type mounted in common on said innermost end and intermediate ramp sections, respectively, at the hinged connection thereof for buttressing both the innermost and intermediate ramp sections according to a selectively adjustable angle formed therebetween.
 10. A Device according to claim 9, comprising self-acting control means for keeping constant the tension imparted to said handling ropes in said lowered working position of said ramp, said winches being phase locked in followup relationship with said control means, said control means comprising at least one sensor member secured to said intermediate ramp section for bearing engagement with said platform with a view to detect any variation in the relative position of said vehicle and platform.
 11. A device according to claim 8, wherein said ramp comprises means enabling said ramp to slew alternately and separately at two vertical swivel axes having stationary locations, respectively, through at least two points of pivotal connection to said vehicle, said points being transversely spaced on the innermost end of said ramp and positioned adjacent to the opposite extreme corners thereof, and means whereby each one of said points of pivotal connection may be releasably held against motion at the position of an associated vertical swivel axis whereas the other point of pivotal connection is freely displaceable in concentric relationship about the former, the geometrical horizontal axis of rotation of the hinged connection between said ramp and said vehicle extending through said points of pivotal connection.
 12. A device according to claim 11, wherein said ramp is releasably connected in a disconnectable manner with at least both aforesaid points of pivotal connection, said points including respectively two hinge members having a common horizontal geometrical axis of rotation, and to two rotary pivots forming corresponding hinge holders each having an own vertical axis of slewing motion, rotatably mounted at stationary locations on said vehicle, each one of said two points of pivotal connection being alternately displaceable separately, when disconnected from their corresponding pivot, in the stationary relative horizontal plane of said common horizontal axis of hinged connection along a path of travel in the shape of an arc of circumference about the other point of pivotal connection retained in a stationary position when coupled to its associated pivot, so as to selectively enable said ramp to rotate through the other point of pivotal connection thereof about the vertical corresponding pivot axis of slewing motion and about said common horizontal geometrical axis of hinged connection of both hinge members.
 13. A device according to claim 12, wherein both aforesaid pivots are located in substantially symmetrical relation to the relative vertical longitudinal centre plane of said vehicle.
 14. A device according to claim 12, wherein each aforesaid hinge member comprises a traveling roller mounted on said ramp at one aforesaid corresponding point of pivotal connection thereof, said roller having its substantially horizontal axle directed substantially at right angles to the relative vertical longitudinal center plane of said ramp in substantially coaxial relationship with said common horizontal geometrical axis of hinged connection, an arcuate track leading from said pivot associated with said point of pivotal connection, each roller being alternately displaceable separately together with said ramp on said tracks, said track being concrete with the vertical pivot axis of slewing motion associated with the other point of pivotal connection and locking means are provided for selectively locking each roller to the associated pivot.
 15. A device according to claim 14, wherein each aforesaid pivot comprises a clevis, a vertical shank integral with said clevis a thrust block forming a footstep bearing carried by said vehicle, said shank being mounted for rotation about its longitudinal vertical axis of slewing motion within said thrust block, the bottom of said clevis being substantially on a level in flush relationship with and gradually merging into the track of said roller corresponding to said pivot, so as to be able to receive and accommodate said roller moving into said clevis betwEen both legs thereof to be supported thereby, and said locking means being provided on said clevis.
 16. A device according to claim 15, including an axle for each roller, and characterized in that the axle of each aforesaid roller comprises a hollow shaft forming a tubular sleeve open at both of its opposite ends and said locking means comprises a post, a removable stop bolt horizontally insertable through said hollow shaft to extend coaxially through said post and horizontally aligned through holes in both legs of said clevis, and a reversible double-acting pressure fluid operated actuator of the linear displacement type carried by said clevis for retracting and extending said stop bolt.
 17. A device according to claim 15, wherein a selective locking means is associated with every relative angular working position of said ramp about any one of said vertical pivot axes of slewing motion for holding said ramp against motion in said angular position, each locking means comprising a yoke for retaining the corresponding travelling roller of said ramp, said yoke being associated with said track which is concentric with said pivot axis for slewing motion at that point of said track which corresponds to the actual instant position of said travelling rotor resting on said track, and locking means for said retaining yoke for locking said travelling roller to said retaining yoke.
 18. A device according to claim 15, further comprising individual locking means for selectively holding each aforesaid pivot against motion in its actual instant angular swivelling position.
 19. A device according to claim 12 comprising an individual reversible drive servo-motor coupled to each pivot for controlling the slewing motion of each said pivot, each said servo-motor comprising a double-acting pressure fluid operated actuator of the linear displacement type with a substantially horizontal longitudinal center line, a radially projecting crank arm fast to each said pivot and said actuator being pivotally connected with one end thereof to a stationary point of said vehicle and with its opposite end to said radially projecting crank arm.
 20. A device according to claim 11, further comprising at least one reversible drive servo-motor for controlling the slewing motion of said ramp about either of said vertical pivot axes of slewing motion, said servo-motor comprising of a double-acting pressure fluid operated actuator of the linear displacement type with a substantially horizontal longitudinal centre line, said actuator being pivotally connected with one end thereof to a stationary point of said vehicle and with its other end to an intermediate point of the innermost end of said ramp.
 21. A device according to claim 1, comprising locking means for holding said ramp against motion in any relative angular position about its vertical axis of slewing motion and at least one stationary stop means for limiting upward swinging motion of said ramp.
 22. A device according to claim 1 comprising also a powered turn-table carrying said posts and winches, said ramp being pivotally connected to said turn-table.
 23. A device according to claim 1 comprising a guide pulley supported on each post for a handling wire rope leading from the associated winch, a pintle for each guide pulley, each said guide pulley being mounted for swivelling motion about said pintle, each said pintle being pivotally connected to a post, each said pintle extending at right angles to the respective axes for rotary motion of said of said guide pulley and of the drum of said associated winch and having its geometrical pivot center line substantially tangential at least to a said guide pulley at the point of tangential engagement of that run of said wire rope which leads from said associated winch, each said pintle being substantially coaxial with at least the adjacent portion of said run of said rope, idler pulleys, said run of said rope passing over a said idler pulley arranged in tangential relation to the geometrical ceNter line of a said pintle and having its axis of rotation positioned at a stationary location in parallel relation to the axis of rotation of a winch drum.
 24. A device according to claim 23 comprising movable pulley blocks and wherein each aforesaid handling wire rope, corresponding to one aforesaid post, passes successively from a said guide pulley to said movable pulley-block with pulleys having a substantially horizontal common axis of rotation, each said movable pulley block being secured to said ramp and free to swivel about a pair of orthogonal pivot axes extending respectively in parallel and perpendicular relation to the geometrical horizontal axis of hinged connection of said ramp, a stationary pulley block for each said handling rope over which a said handling rope passes and having a stationary fastening point for the dead end of a said rope, each said stationary pulley block being connected to a said post and being free to swivel about a pair of orthogonal pivot axes one of which is at least approximately perpendicular to said geometrical axis of hinged connection of said ramp.
 25. A device according to claim 23, wherein said ramp consists of at least two successive hingedly interconnected, first inner and second outer ramp sections, and said second ramp section may be folded back downwards against said first ramp section, a stationary pulley block mounted on said first ramp section, a movable pulley block, an operating wire rope mounted on said second ramp section for controlling the relative unfolding motion of said second ramp section, a pair of guide pulleys, said rope being successively reeved over said pair of guide pulleys pivotally connected each one to an associated aforesaid post through a substantially horizontal pivot shaft extending at right angles to the axis of rotation of said guide pulley, whereas those two runs of said wire rope, which lead from said guide pulleys respectively towards said ramp, pass each one several times successively and alternately around said movable pulley block mounted on said second ramp section and on a stationary pulley block mounted on said first ramp section and means for automatically tensioning and taking up the slack of said rope, making said rope fast with its dead end at a fixed point of said stationary pulley block.
 26. A device according to claim 25, wherein each aforesaid guide pulley comprises guide means for keeping that run of said wire rope, which leads tangentially into said guide pulley and that run of said rope which leads tangentially from said pulley substantially in a same centre plane of said guide pulley, which plane is perpendicular to the axis of rotation of said guide pulley.
 27. A device according to claim 26, wherein each aforesaid guide pulley comprises a pair of hollow cable-guide members through which both runs of said wire rope slidably extend, respectively, while being tangential to said guide pulley, and two supporting arms for each cable guide member rotatably mounted endwise on the shaft of said guide pulley, each said cable guide member being rotatable between a said two supporting arms.
 28. A device according to claim 25, including a third outermost end ramp section for resting on an outside platform, said third ramp section being hingedly connected to said second ramp section and carried by the latter, and damping and shock-absorbing means on the underside of said first ramp section to form a resilient buffer-like stop means for said third ramp section in the folded configuration of said ramp.
 29. A device according to claim 1 including a substantially horizontal turn-table carried on said vehicle, means for pivotally connecting said ramp to said turn-table, and motor means for reversibly rotating said turn-table for effecting slewing motion of said ramp.
 30. A device according to claim 1 including a substantially horizontal turn-table carried on said vehicle, means for pivotally connecting said ramp to said turn-table, said posts and said winches being carrieD by said turn-table, a curved rack concentric with said turn-table, gear means meshing with said rack and reversible motor means for driving said gear means for effecting slewing motion of said ramp.
 31. A device according to claim 30 including a speed reducing means for said gear means.
 32. A device according to claim 30 wherein said curved rack is stationary with respect to said turn-table and said motor means is carried on said turn-table.
 33. A device according to claim 30 wherein said curved rack is carried by said turn-table and said motor means and gear means are stationarily supported relative to said turn-table.
 34. A movable device forming an access ramp to interconnect a vehicle and an outside platform, said ramp being pivotally connected to the vehicle so as to be swingable upwards into an inoperative substantially upstanding position stowed on said vehicle and downwards into an operative outward projecting working position, wherein the improvement consists in that said ramp comprises means for variable connection to said vehicle so that it may be slewed in parallel relation to a horizontal plane about at least one substantially vertical geometrical swivel axis whereby in its lowered configuration, the relative angular position of its longitudinal direction is selectively adjustable with respect to said vehicle, said last-named means comprising posts, at least two selectively operable winches associated with said posts and at least two handling ropes connected between respective of said winches and said ramp and selectively windable up on said winches, a guiding runway provided on said vehicle and providing a substantially flat curved path of travel, a truck movable along said guiding runway, and means for pivotally connecting said ramp at its innermost end to said truck, said truck and its runway being located below the level of the floor of said vehicle, a plurality of transversely juxtaposed flap elements pivotally connected to the adjacent inner end of said ramp which may be folded back against said ramp and downwards onto said floor of said vehicle to cover and span said truck and its runway for restoring the continuity of passageway between said ramp and said floor.
 35. A movable device forming an access ramp to interconnect a hold of a vehicle and an outside platform, said hold having an access opening and beng defined between a lower deck of said vehicle, and an intermediate deck, an uper deck on said vehicle overlying said intermediate deck, said hold having a port opening through which it may be loaded, closure means for said port opening, and means for operating said closure means to open and closed positions relative to said opening, said ramp comprising an innermost end section, an intermediate section and outermost end section, means for pivotally connecting said sections to each other about relative horizontal geometric axes of rotation, wheeled means at the inboard end of the innermost section for pivotally connecting the two transversely opposite end sides of said inboard end about a horizontal geometric axis of rotation relative to the lower deck, arcuate guide runway means on the lower deck of said vehicle in which said wheeled means are guided, posts at said upper deck, winches associated with said posts, and handling ropes connected between said winches and one of the sections of said ramp for raising and lowering said ramp and also effecting horizontal slewing action of said ramp in relation to at least one substantially vertical curved axes.
 36. A device according to claim 35 comprising also a powered turn-table carrying said posts and winches, said ramp being pivotally connected to said turn-table.
 37. A device according to claim 35 comprising also means to lock said ramp sections in lowered and raised conditions and also in selected slew positions relative to said vehicle.
 38. A device according to claim 35 including buttressing means to selectively lock the pivotal connection between the innermost ramp section anD intermediate ramp section so as to render them equivalent to a rigid continuous beam.
 39. A device according to claim 35 including locking means on the intermediate deck to retain the innermost ramp section folded back in the raised condition of said ramp. 